Liquid-crystalline compounds have been disclosed, inter alia, by B. D. Demus, H. Demus and H. Zaschke (Flussige Kristalle in Tabellen [Liquid Crystals in Tables], 1974; D. Demus and H. Zaschke, Flussige Kristalle in Tabellen II [Liquid Crystals in Tables II], 1984, VEB-Verlag Leipzig). Mesogenic groups are also described therein, i.e., groups whose presence in a molecule may give the opportunity for the occurrence of liquid-crystalline phases.
Organocyclosiloxanes containing mesogenic side groups are described in U. S. Pat. No. 4,410,570 (published Oct. 18, 1983, F. H. Kreuzer et al., Consortium fur elektrochemische Industrie GmbH) in which the liquid-crystalline organocyclosiloxanes have mesogenic groups bonded to the respective silicon atom via a propyleneoxy group. They were prepared by the addition reaction of allyloxy benzoates with a cyclosiloxane containing Si-bonded hydrogen atoms. Siloxanes of this type tend to eliminate propene, forming SiO-C bonds which are hydrolytically unstable.
It is an object of the present invention to provide substances containing mesogenic side groups which have liquid-crystalline properties. Another object of the present invention is to provide substances containing mesogenic side groups having liquid-crystalline properties which can be easily oriented. A further object of the present invention is to provide substances containing mesogenic side groups which have liquid-crystalline properties which are chemically stable.